1. Field of the Invention
The present invention relates to an inkjet printer adapted to discharge ink through nozzles at an inkjet head to make a record on a recording medium, and a maintenance method of inkjet head.
2. Description of Related Art
Inkjet printers sometimes suffer from precipitates attached to nozzles in a set of inkjet heads due to developments of ink solvent evaporation such as while running or in a waiting mode. Such attached matter tends to cause discharge troubles such as failed discharge or disordered ink discharge directions at nozzles, resulting in a debased record quality.
There are inkjet printers employing maintenance operations as solutions to eliminate discharge troubles due to such attached matter. As a known maintenance operation, there is a flushing operation to be performed between printing services by discharging unused ink after printing to remove attached matter and so on from nozzles. As another known maintenance operation, there is a purge operation making use of an ink supply line as a route to an inkjet head in a pressurized state for pressing ink to spill out of nozzles, while using wipers to remove spilt ink together with dusts adhering on the face of nozzle header.
Flushing operations afford to apply higher pressures to individual nozzles than purge operations with higher efficiencies to remove attached matter from nozzles. Such flushing operations need an implement for receiving discharged ink and ink mist attending the discharge. To this point, there are known printers provided with a tray-shaped ink receiving member to be set in flushing operation in a position under inkjet heads to receive ink, ink mist, and others.
However, in some cases, even if such an ink receiving member is provided under inkjet heads, there is an open space lying between the ink receiving member and inkjet heads, thereby leaving discharged ink particles and ink mist as they are free to float and causing contamination in the printer. In particular, when flushed under a condition having foreign matters or viscosity-increased ink residing in nozzles, there occur disordered discharge states including fine mist-like ink droplets propelled outside or fluxes of ink discharged failing to go in normal downward directions. There is an attending anxiety about increased ink mist floating in the printer, thereby causing worse contamination in the printer. Even in cases raising nozzle pressures for enhancing performance in discharge restoration, there likewise occur disordered ink-discharging states with increased tendencies, thereby having worse contamination in the printer.
There are techniques proposed in Japanese Patent Application laid-open Publication No. 2004-106304, including a flushing operation using caps for covering nozzle header faces of inkjet heads, while operating a suction pump for collecting discharged fluxes of ink and ink mist in the caps. This arrangement is effective to suppress contamination due to discharged ink particles or ink mist in the printer.